Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: masonmart on February 23, 2016, 06:42:49 PM
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The CB550 has a code on the crankcase (A,B,C) based on main bearing support ID measurement and a mark on the crank (1,2) based on crank journal dia and from these codes any one of 4 main bearings (brown, black, green, yellow) can be selected to fit well.
None of the usual outlets like CMSNL or Dave Silver have all 4 bearings.
If you damage a crankcase and wish to replace it say with one from a breaker but the existing main bearings aren't compatible with the casing ID's is there anything that can be done if you can't buy the correct main ?
Are there any other outlets that may make Honda main bearings now?
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Go for a full set of Black or Green with a bit of graphogen and run in. That's if you can get them.
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Ok show myself up as the ameteur I am. What is graphogen?
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Its a Graphite based assembly paste. The hype says an engine built with just Graphogen can run without oil for a while. Wouldn't try that myself though. I've used it a bit now since Trigger recommended it and its bloody good stuff. Expensive as well.
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So would one apply it to bearing surfaces only in crank and cam. Or cam lobes / followers too etc?
Just googled price. Jesus it better be good! Take it you dont need much per build though?
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Any surface that needs bedding in, some engine builders even use it on the bores and pistons but, I prefer oil on those parts.
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The crankcase codes are CBBBC as stamped on the rear of the crank cases and the crankshaft journals are all 1.2995" dia (32.99mm) so I need 2 B (brown) bearings and 3 C (green) bearings. I can see the bearings at DS but the manual says not to use the letters stamped on the cases although these would seem to align with main bearing codes and the number of letters matches up.
I guess that the only way is to measure the main bearing slots in the crankcase and use the measured value rather than that stamped on the cases?
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Use the case stampings as the cases dont wear(unless the shells sieze to the crank and spin), its the crank journals that wear and then rarely
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Just to Clarify; the Crankcases don't wear; unless the bearing siezes and spins the half bearings in the Crankcases,
The Crankshaft wears; and the Bearings wear.
You disassemble the Crankcases, and measure the wear with Plastiguage.
That tells you the wear on your crank main journals.
You select new Journals from the FSM to fit your crankshaft wear.
You go online to buy new Journals. But the usual suppliers don't have all the colours you need.
What can you do?
Probably your old half shells have more than enough meat on them to reuse!
Clean Oil, regular oil changes and TLC will keep your engine going for another 40 yrs!
HTH
NIGEL.
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I'm talking bollox sorry, the crank journals are diameter 2 and for C2 and B2 I need Black and Brown respectively not Brown and Green.
The part number for the black bearings is 13315-323-000 but so far I can't see any anywhere.
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Many thanks